This invention is to provide an improved processing method and structure for the packaging technique of a large size field emission display. The spacer was efficiently fixed on the upper plate through an anodic assembling technique to save the processing and its thickness.
The screen of various electrical equipments such as computer, television, and cellular phone is the best communication bridge between person and electrical equipment. The cathode ray tube (CRT) has been the principal device in the past years since it demonstrates rich color, high resolution, brightness, high contrast, wide viewing angles, rapid speed, and cheapness. But the requirements of today's screen are not only for high-resolution, natural color, light thin volume, low radiation, and low electricity consumption; but also the more important requirement is to satisfy the mobile demand such as cellular phone and automobile display. Thus, the development of CRT screen was limited very much.
Replacements of CRT screen are like liquid crystal display (LCD), electro luminescent display (ELD), plasma display panel (PDP), vacuum fluorescent display (VFD) etc. Most of them are very expensive and are not very efficient except LCD. But LCD still has the following limitations:    1. Point distance is too long, picture is not soft;    2. Reaction is too slow, ghost shadow is easily formed;    3. Brightness is not enough, not suitable for the outdoors use.
Hence, it needs not only to have all advantages of LCD, but also to overcome all limitations described above to satisfy all requirements of screen.
Field emission display (FED) has not only soft picture, rapid reaction, and clear brightness like CRT, but also possesses characteristics of lightness of flat display and low performance consumption.
An upper plate called anode plate and a lower plate called cathode plate assemble FED. Having processed the upper plate and the lower plate, then assembling these two plates, the formation of the space between the upper plate and the lower plate was vacuumed to 10−5˜10−7 torr and readily for the next process.
The size of FED increases resulting the center of glass flat of the vacuumed space between the upper plate and lower plate becomes very hard and fragile due to the atmosphere pressure. In order to solve this problem we put multiple spacers at the suitable positions between the upper plate and the lower plate to increase the tolerance of glass flat for the atmosphere pressure, also to decrease the fragile possibility of the glass flat.
FIG. 1 show a conventional FED device, after the processing of the upper plate 1 the spacers 2 were fixed on the upper plate 1, then proceeding the aligner process of the upper plate 1 and lower plate 3. There are two methods for the fixing of spacers 2 on the upper plate 1 as follows:    1. As shown in FIG. 2, after the processing of the upper plate 1, the binding layer 12 was put on the upper plate 1, then, the spacers 2 were bonded on the binding layer 12.    2. As shown in FIG. 3, after the processing of the upper plate 1 increasing one more process in which the formation of the slots 13 was on the upper plat 1 and the spacers 2 were bound on the slots 13.
Methods described above show the fixing of the spacers 2 on the upper plate 1, but the limitations are as follows:    1. Both of methods need to increase the process and the cost.    2. The fixing of the binding layer 12 on the spacers 2 will increase the thickness of FED due to the binding layer 12.    3. In the method of the fixing of the spacers 2 using the slots 13, the spacers 2 were only bonded on the upper plate 1; the spacers 2 will drop off during the aligner process of the upper plate and the lower plate due to vibration of the moving process and the other unpredictable strength.